'use strict';
const axios = require('axios');
const urlJoin = require('url-join');
const semver = require('semver');

function getNpmInfo(npmName, registry) {
    if (!npmName) {
        return null;
      }
    const registryUrl = registry || getDefaultRegistry();
    const npmInfoUrl = urlJoin(registryUrl, npmName);
    console.log(npmInfoUrl)
    return axios.get(npmInfoUrl).then(response => {
        if (response.status === 200) {
          return response.data;
        }
        return null;
      }).catch(err => {
        return Promise.reject(err);
      });
}

function getDefaultRegistry(isOriginal = false) {
    return isOriginal ? 'https://registry.npmjs.org' : 'https://registry.npm.taobao.org';
  }

  async function getNpmVersions(npmName, registry) {
    const data = await getNpmInfo(npmName, registry);
    if (data) {
      return Object.keys(data.versions);
    } else {
      return [];
    }
  }

  function getSemverVersions(baseVersion, versions) {
    return versions
      .filter(version => semver.satisfies(version, `^${baseVersion}`))
      .sort((a, b) => semver.gt(b, a) ? 1 : -1);
      // .sort((a, b) => semver.gt(b, a));
  }

  async function getNpmSemverVersion(baseVersion, npmName, registry) {
    const versions = await getNpmVersions(npmName, registry);
    const newVersions = getSemverVersions(baseVersion, versions);
    if (newVersions && newVersions.length > 0) {
      return newVersions[0];
    }
    return null;
  }
  async function getNpmLatestVersion(npmName, registry) {
    let versions = await getNpmVersions(npmName, registry);
    if (versions) {
      return versions.sort((a, b) => semver.gt(b, a))[0];
    }
    return null;
  }

module.exports = {
    getNpmInfo,
    getNpmVersions,
    getSemverVersions,
    getNpmSemverVersion,
    getDefaultRegistry,
    getNpmLatestVersion
};